How to access an add-on container from local network

I have installed Home Assistant OS and Raspberrymatic as add-on.
Access from Homassistant is working fine.
I want to access the container via SSH from my local network which is not working so far.

the add-on is in a different network:
Is there a way to forward the add-on port to the end0 interface?

First thing to check : is there a ssh-server running in the add-on?

Sure, i can ssh into the container if i am on the same machine.
It is no working from a different machine in the same LAN.